不同荷载模式下锈蚀钢筋力学性能研究

Study on mechanical performance of corroded reinforcement bar under different loading modes

基于不同荷载模式下锈蚀钢筋力学性能试验,分析了单调拉伸荷载、重复荷载及疲劳荷载作用下锈蚀钢筋的力学性能,对锈蚀钢筋力学性能在不同荷载模式下退化程度进行了对比研究,并给出了锈蚀钢筋力学性能退化计算式。试验表明,随着锈蚀率的增大,疲劳荷载及重复荷载下锈蚀钢筋力学性能退化比单调荷载下更为明显,伸长率及弹性模量退化相对严重,疲劳及重复荷载下锈蚀钢筋由软钢逐渐向硬钢转变,而坑蚀是导致这一现象的主要原因之一。坑蚀是应力集中源,同时也是锈蚀钢筋混凝土结构损伤累积源,建议对锈损结构疲劳及抗震性能评估应考虑这一因素的影响。

Through experiments of mechanical performance of corroded reinforcement bar under different loading modes, the effect of corrosion on mechanical property under monotonic tensile load, low cyclic load and fatigue load have been analyzed. Comparison of mechanical performance degradation of corroded reinforcement bar under different loading modes has been studied. Calculated mode for the mechanical performance degradation has been established. The conclusion showed that along with the accretion of rusty ratio, under low cyclic load and fatigue load, the mechanical performance degraded more seriously than that under monotonic tensile load. The degradation of e- longation and elasticity modulus is comparatively serious, and the yielding plateau gradually shortened, and even disappears under low cyclic load and fatigue load. For this reason above all, pitting corrosion is where stress con- centration and damage accumulation of corroded reinforcement concrete structure happen. Thus the influences of pitting corrosion should be taken into account while evaluate fatigue behavior and seismic performance.